For high-energy x-rays and gamma rays which have high transmittance, a sensor, made from materials having a high absorbing ability, that is having a high atomic weight, is used. Examples of these materials are CdTe, CdZnTe, HgI2, PbI2 and TlBr, and sensor elements made from these materials are arranged linearly or two-dimensionally, and current is read from an electrode attached to each element. The current which is read is pre-amplified, signal processing is performed thereon, and two-dimensionally arranged image signals are generated.
Normally in the case of a linear sensor, elements are arranged in a row, and signals are guided to the pre-amplifier via the wires disposed at equal spacing. In Japanese Patent Application Laid-Open No. H5-236210, it is proposed that the sensor sections are arranged in shifted positions in order to increase resolution in the linear sensor.
In the case of a semiconductor sensor, the capacitance between the pre-amplifier and the sensor has a major influence on the read signals, but in the case of a visible light sensor which can handle a large signal current amount, the influence thereof is minor, and can be adjusted in the signal processing in a subsequent step.